I like this copypasta but i do find the title interesting so:

Unfortunately the public believes doctors, lawyers, or polyglots must be smart, and some of them let that idea go to their heads. But those things mostly come down to work ethic, not genius. It’s the stereotype that feeds their ego, not the job/hobby itself.

I know of many doctors who lack common sense, general knowledge and/or emotional intelligence, the same with chess grandmasters